Read again! The master is obviously good old Uncle Sam
I ain't sure.
o.k., shortly after that passage, he's talking to "Sir Sam".
and taking your find on Shakey:
Though we know that almost every time, Buk mentions Shakey, he's talking Against him - this doesn't neccessarily mean, he wasn't - somwhow - 'influenced' by his style, say, shortly after reading him (which we know he did).
(and we all know from our own reading: after an hour of reading, you often start to even THINK in the writing style of the guy you just read.)
I wouldn't be surprised, if Buk had read Shakey shortly before writing this.
In Shakey's plays, the naming of a "master" usually comes from a servant/slave, of course. And sure, Buk feels himself being a slave to some 'master' in this sense here.
This again points to "Sir Sam".
Only I sense him argueing against something bigger as any gouvernment, I feel he's mourning against a certain constitution (is this the word?) of Life in General.
This includes (1) not only 'Sam', but EVERY 'boss' who forces his employees to work like hell.
And (2) includes (as I see it) also 'God' or some 'higher forces' or even Life in general - at least I think his laments, since they're not only pointed on his job but also on the alternative (other people have) to be 'drunk, fuck, sing' etc. which he cannot have, point more against the life-situation itself than accusing the soup or 'Sam' only.
B.t.w.: IF he's refferring to This Shakey-monologue in Any way - let's have a look at the play where it's in ('As You Like It'):
It's build around this same contrast/polarity of sterile court-life (where the master-servant/slave situation dominates everything) vs the Free Life in the woods. And with Shakey too, this is only one concrete story to state a message about the problem in General.
I don't say, it IS so. Only I throw in some possies.
(and the worst thing: being no native-speaker I'm not even able to handle the language proper and not sure I really got anything right. sorry, kids.)